The present invention generally relates to a pick-up assembly for use in a video disc player and, more particularly, to an improvement in a fly lead used in the pick-up assembly for providing a signal transmission line and also a support for the pick-up stylus relative to the displacement in a direction laterally of and/or perpendicular to a video disc placed on a turntable.
As is well known to those skilled in the art, a video disc player of the CED system utilizes a pick-up assembly generally of a construction shown in FIG. 1 of the accompanying drawings. Referring to FIG. 1, the pick-up assembly comprises a generally rectangular casing 1, a cantilever 2 having one end connected to the casing 1 in a known manner, a stylus carrier 3 carried by the opposite end of the cantilever 2, a stylus 4 generally made of diamond and mounted on the carrier 3 so as to extend generally at right angle to the carrier 3 and a fly lead 5 made of electroconductive and resilient material and serving concurrently as a signal transmission line through which a video signal picked up by the stylus 4 from a video disc is transmitted to an external electrical circuit and as a support for the stylus 4 relative to the displacement in a direction laterally of and/or perpendicular to the video disc on a turntable. According to the prior art, in order to assuredly connect the fly lead 5 to one end of the diamond stylus 4 opposite to its pointed end, the diamond stylus 4 has a relatively great length l.sub.1 so that that end of the stylus 4 opposite to its pointed end can project beyond the stylus carrier 3 a length c which corresponds to the balance of the length l.sub.1 less the sum of the length b over which the pointed end of the stylus 4 extends downwards from the carrier 3 and the length a of a generally intermediate portion of the stylus 4 which extends across the thickness of the carrier 3, as shown in FIG. 2. In this known construction, the greater the length c, the easier it is to connect the fly lead to the stylus. However, the greater the overall length of the stylus, the higher the manufacturing cost of the pick-up assembly. This is because the diamond is the most expensive material for the sytlus. Examples of the above discussed prior art are found in, for instance, the Japanese Laid-open Patent Publication No. 52-37004 (laid open to public inspection on Mar. 22, 1977) and No. 56-119950 (laid open to public inspection on Sept. 19, 1981, and corresponding to the U.S. patent application No. 118240 filed Feb. 4, 1980 in U.S.A.).
In order to minimize the manufacturing cost without reducing the rigidity of connection of the fly lead to the diamond stylus, the Japanese Laid-open Utility Model Application No. 56-90747 (filed by the assignee of the present invention on Dec. 14, 1979 and laid open to public inspection on June 14, 1981) discloses such an arrangement such as that shown in FIG. 3. Referring to FIG. 3, the stylus carrier 3' has an inclined face 6 on which a projection 7 is rigidly mounted. The stylus carrier 3' also has an upright end face 8 continued to the inclined face 6, the stylus 4' being rigidly secured to the upright end face 8 without permitting one end of the stylus 4' opposite to the pointed end to project upwardly beyond the upright end face 8. One end of the fly lead 5' is positioned on the inclined face 6 with the projection 7 extending therethrough and is electrically connected to the stylus 4' through a continuous electroconductive layer 9 deposited on the faces 6 and 8.
The arrangement shown in FIG. 3 requires the employment of an electrodeposition of an electroconductive material to form the layer 9 over a relatively large surface area ranging from the end face 8 to the inclined face 6, and accordingly, the cost required to perform the electrodeposition reflects upon the price of the resultant pick-up assembly, rendering the cost of the latter comparable to that of the pick-up assembly of FIG. 2, even though the required length l.sub.2 of the stylus is smaller than that shown in FIG. 2.
Accordingly, the present invention has been developed with a view to substantially eliminating the disadvantages and inconveniences inherent in the prior art and proposed pick-up assemblies and has for its essential object to provide an improved pick-up assembly for a video disc player, which utilizes a stylus of relatively small length, which can be manufactured at reduced cost without employing the expensive electro-deposition technique, and of which characteristics can be improved with decreasing the noise in operation.
According to the present invention, the above described object of the present invention can be advantageously and effectively accomplished by providing an improved pick-up assembly which comprises a generally elongated stylus of generally rectangular cross section and having an electrode provided on one surface of said stylus so as to extend lengthwise thereof, a generally elongated stylus carrier having first and second support faces defined at one end thereof so as to lie at right angles to each other, said stylus being secured to said first and second support faces with said one surface of said stylus facing in a direction away from said carrier, said stylus so secured extending generally transversely of the longitudinal axis of the carrier, and a generally strip-shaped resilient fly lead having one end bent to protrude generally perpendicular to the remaining portion thereof, said bent end being physically and electrically connected to the electrode by the use of an electroconductive bonding agent.
These and other objects and features of the present invention will become readily understood from the following detailed description made in connection with a preferred embodiment thereof with reference to the accompanying drawings, in which;